Delayed-action mercury-tube switch



Dec. 23, 1930. l. E. MccABE DELAYED ACTION MERCURY TUBE SWITCH Filed May28I 1928 INVENTOR. 11E/1 E.' MC 6,455

ATTORNYS.

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---UWMHMMMMMMMMMH Patented Dec. 23, 1930 UNITED STATES IBA E. MOCABE, 0FCHICAGO, ILLINOIS DELAYED-ACTION MERCURY-TUBE SWITCH Application led May28,

This invention relates to improvements in mercury to mercury make andbreak electric switches and more particularly to a delayed actionmercury tube switch of this character.

It is an object of this invention to provide a mercury tube switch inwhich one terminal is isolated in a bath of mercury within a containerof insulating material normally floating upon the main body of mercuryto which the other terminal connects, with the connection between theterminals normally broken and means to intermittently submerge thecontainer in the main body of mercury to close the circuit between thesaid terminals and then release the container to emerge and break thesaid circuit. It is also an object of this invention to delay the normalmovement of the container in submerging and emerging. It is a furtherobject of this invention to provide an automatic means to alternatelycause the submergence and release of the container actuated'by thecircuit controlled by said switch.

While the preferred form of this invention is illustrated upon theaccompanying drawing for one of the many uses of this device, it is tobe understood that minor detail changes may be made without departingfrom the scope thereof, and the applicant is notv limited to the useillustrated and hereinafter described.

In the drawings:

Figure 1 is a new inside elevation of one form of this improved device,with parts broken away, illustrating its use in an automatic signflashing system, with the wiring and lights of the system shown indiagram and with the insulating container floating upon the main body ofmercury and the circuit through the switch broken.

Figure 2 is a top plan view of the container and the switch tube insection taken on the line 2-2, Figure 1.

Figure 3 is a view in transverse vertical central section of the mercurytube with the container floating in the mercury with the circuit broken.

Figure 4 is a similar view with the container submerged and the circuitclosed.

In carrying out this invention an hermeti- 1928. Serial No. 281,028.

cally sealed tube 1 of insulatin material, preferably glass, is filledabout ha f full with mercury 2 and the air thereabove exhausted and aninert gas preferablyubstituted therefor before sealing. Before sealing,a cylindrical container 3, closed at the bottom and having outwardlyaring upper edges, formed of isolantite, quartz or other insulatmgmater1al and provided with an outerl sheathln 4 of magnetic metal,preferably iron, an immovably secured thereto, is inserted in the tube.The container 3 is of such dimensions that when the tube is held with1ts greater dimension in a vertical plane and the container filled withmercury it will ioat with its upper ared ed es a substantial distanceabove the surface o the main body of mercury. Lead in wires 5 and 6 areseated in each end of the tube, the lower lead in wire 5 contacting withthe main body of mercury below the bottom of the container 3 and theupper lead in wire 6 prolonged to enter the center of the container 3.This prolonged lead in wire 6 terminates in a cylindrical electrooe 7secured at its center and at right angles to the lead in wire. Theprolonged lead in wire 6 is of such length that when the container 3 isiioating normally upon the mercury, the electrode 7 will be adjacent thebottom of the interior of the container and the electrode 7 is of such adiameter as to be just received within the container 3 and slide thereinwithout friction. A notch 8 or small aperture is provided in theperiphery of the electrode 7 whereby the mercury in the container canpass from one side of the electrode to the other.

An electromagnet 9 is arranged about the tube 1 with its coils supportedin such a relation thereto that when energized it will draw the ironsheathed container 3 downward until it is submerged within the main bodyof the mercury` 2, as shown in Figure 4, and when deenergized will allowthe top of the container to emerge, as shown in Figure 3. The normalmovement of the container 3 in submerging and emerging is de layed bythe fixed notched circular electrode 7 and the rate of movement can beregulated by the size of the notch'8` in the electrode.

The lead-in wires 5 and 6 are connected in the circuit to be controlled.Thelead-in wire 5 is in electrical contact with the main bod of mercuryabout the container 3 and the cad-in wire 6`is in electrical contactwith the mercurywithin the container and is thereby isolated from themain body of mercury when'the container is normally oating in the mainbody and the circuit between lead-in inner `5 and 6 is broken. When theelectric ma et 9 is energized and the container 3 su merged within themain body of mercury, the circuit between the lead-in wires 5 and 6 willbe completed through the main body of mercury coming in contact with themercury contained withinthe container 3. As the container submerges themain-body of mercury overflows the outwardly flared toipnpr rim to makea quick, positive and de 'te electrical connection where'it contactswith the mercury within the container. As the container vemerges theelectrical connection positive and definite severance as Vthe outwardlyflared top of-the container cleaves through the surface 'of themercury'witbin which it has been submerged.

This mercury to mercury make and break `delayed action switch isillustrated as em# ployed to control an electrical sign flashingcircuit, as shown in Figure 1. In this application the lead-in wires'and 6 are connected in series with the incoming current from thecommercial line by wires 10 which pair about an electric sign 11 andthen by wire 12 back to the commercial line. The coils of the electricmagnet 9 are connected in a shunt circuit 13 about the delayed actionswitch. In this arrangement when'the circuit is broken through theswitch the current will pass through the electric magnet 9 which is ofsuch construction tooifer Suilicient resistance to prevent the lamps'.14 from lighting and the flow of current through the coils energizethe magnet to draw the magnetic metal sheathed container 3 downwardbelow the surface of the main'body of mercury to close the contactbetween the lead-in wires ott' the switch and thereafter the 'coils ofthe magnet will be shunted out and the current iiow through the lamps.vAls-soon as `this takes place, the buoyancy of the container, beingreleased from the magnetic force, causes-it to rise to break the circuitthrough the switch and again energize the magnets as the top of thecontainer cleaves through the surface of the mercury.

It is obvious that the rate of movement can be determined by the size ofthe notch 8 cut in the cylindrical electrode 7 before it is fixed in thetube and it may also be raised by the relation of the coils of themagnet about the tube 1 to the surface of is broken by a quick the mainbody of the mercury in the tube l before the parts of the apparatus aresecured in fixed position. It is also obvious that a fixed magnet may beemployedfor the same purpose which may be caused, by any desiredmechanical means, to move up' and down about theatube to cause thecontainer 3 to be submerged and emerge from the main body of the mercuryto make and break `the circuit to the lamps. It is also obvious thatwhen a quick make and break is desired the `cylindrical electrode 7 maybe omitted. The device as illustrated is of such design that it may beproduced by automatic glass making machinery.

What I claim is:

l. A delayed action mercury tube switch comprising a glass tubecontaining a body of mercury and an insulatin container having acylindrical boreI wit an open top therein containing mercury normallyfloating upon the main body of'mercury and isolating thesmaller bodtherefrom, a lead in Wire in contact with't e main body of mercury, alead in wire normally out of contact with the main body and in contactwith the isolated body of mercury terminating in a piston like electrodein the container bore, and means to cause the open topof the containerto submerge and emerge in vthe main'bod of mercury to make and break an-electrlcal contact between the lead in wires,'the rate of movementbeing determined by the size of the piston like electrode.

2. A mercury tube electric switch comprising a sealed glass-tubecontaining a body of mercury with a container of insulating materialhaving an unobstructed opening in the top thereof normally floatingthereon, containing an isolated smaller body of mer? cury therein andhaving a sheathing of magnetic. material thereabout below said open top,electrodes-sealed in the glass tube, one in contact with the main bodyof mercury and one in contact with the smaller isolated body, and amagnet about the glass tubes adapted to cause the top of the magneticsheathed container to submerge and emerge in the main body of mercury tomake and

